As can be seen by reference to the following U.S. Pat. Nos. 3,343,265; 909,023; 4,446,627; and 4,562,649; the prior art is replete with myriad and diverse angularly adjustable measuring instruments.
While all of the aforementioned prior art constructions are more than adequate for the basic purpose and function for which they have been specifically designed, these patented arrangements are uniformly deficient not only with regard to the complexity of their locking mechanisms but also with respect to the fact that they did not contemplate the need for removable indicia sleeves to accommodate for situations wherein different scale drawings are to be measured, using the same basic measuring instrument structure.
As a consequence of the foregoing situation, there has existed a longstanding need particularly among those individuals who deal with a variety of different scale drawings for a new type of multi-scale and multi-orientation measuring apparatus to assist them with myriad measuring tasks; and, the provision of such a construction is a stated objective of the present invention.